Carburetor ice warning gauge



Aug. 14, 1945. C'ARSSQW 2,382,365

CARBURETOR ICE WARNING GAUGE Filed Nov. 28, 1941 2 Sheets-Sheet 1 INVENTOR.

1945' J. F. ARssow 2,382,365

GARBURETOR ICE WARNING GAUGE Filed Nov. 28, 1941 2 Sheets-Shet 2 INVENTOR. 5 $.00)

I fl rromvsv Hahn F C temperatures.

.the temperature of the air.

' Patented Aug. 14, 1945 'cmnuan'ron. ICE WARNING GAUGE John F. Carssow, Los Angeles, Calif., alsignorto Sam M. Jarvis, Glendale, Ferris I. Palmer, Bur! bank, and Erwin Fetschlre, Glendale, Calif.

Application November as, 1941, Serial No. 420,829

(01. zen-1) i Claims.

This invention relates to a device for indicating the formation of ice in fuel carburetors, and also to devices for the prevention and for the removal of ice formed in fuel carburetors. 1

Ice formation is one of the most importan problems in. carburetion in which volatile fuels are employed, such as in gasoline carburetors. This is particularly so in gasoline carburetors which may be subjectedto low temperatures and pressures, as carburetors for'-airplane engines. The formation of icein the carburetors and fuel to which the engine carburetor and fuel passages are subjectedas a result of low atmospheric While such low temperatures may result inicing becausev of the freezing of the water vapor in the air used in carburetion, it may also arise when the outside air temperatures are as high as 50 to 65 above zero. A certain percentage of the fuel entering through the carburetor jet vaporizes. The latent heat of vaporization of this fuel is abstracted from the environment which surrounds the jet, to wit, the walls of the fuel passages, thus causing. a refrigeration effect whichmay cause a drop of 40 to 80 F. in

of air flow results in a richer mixture and in an immediate loss of power.

Since ice accumulation may occur almost instantaneously due to sudden change of atmospheric conditions or changes in altitude, the pilot is without warning until he discovers by a loss in engine R. P. M., or engine roughness, or stickingthrottle, that his carburetor has iced up. It has been said that .this has caused many of the forced landings for which no other reason could be assigned. Ice also tends to form when the pilot is shooting a landing." In such case, the throttle is partly closed and the manifold vacuum is high, thus increasing the refrigeration effect.

Sudden icing in such case may be critical, since The efl'ect of this passages creates one of the great hazards in the Various expedients have been worked out to remove the ice which has been formed. These include the injection of a mixture of. alcohol and glycerine which softens the deposited ice to a degree which permits the fluid stream to carry the ice out of the carburetor. Other methods include the preheating of the air to raise the temperature to a point which prevents further icing and removes deposited ice.

In'either method, it is desirable to limit the amount of the treatme'nt,'since both are deleterious to engine efliciency. The mixture of glycerine and alcohol dilutes the fuel and causes a loss of engine power. Too much heat or the prolongation of the preheating of the air beyond the time necessary to remove ice is deleterious, since it causes a loss of engine power. Extreme care must be taken in the control of the proportioning device whereby the heating of the air and its mixing with cold air is controlled. Faulty operation of thiscontrol may result in destructive detonation, resulting possibly in serious damage to the power plant.

It is an object of this invention to provide an accurate warning of the formation of ice in carburetors, particularly in airplane carburetors, and

in carburetors of other vehicles subject to icing conditions.

It is another object of this invention to provide a warning of the continuance of the formation of ice in such carburetors.

It. is a further object of this invention to provide a carburetor ice warning gauge whereby the degree of icing may be indicated.

It is a further obiect'of this invention to provide a de-icing system whereby an agent capable of removing ice formed in the carburetor is automatically provided responsive to the above ice warning systems. a

It is a further object of this invention to provide an anti-icing system whereby upon the warning produced by this invention, conditions in the carburetor system maybe automatically provided, whereby the productionof ice is either minimized or prevented.

In a general sense this invention provides means which is responsive to the accumulation of ice, whereby an electric circuit is controlled to indicate the existence of ice.

In a more specific form the accumulation of ice in the venturi of the carburetor causes a dethe ice and also, or alternativeLv, automatically discontinues' the operation of the anti-icing and the de-icing mechanism.

Further, or alternative means, may be provided to indicate the accumulation of ice at the throttle butterfly. This means in a general sense will indicate by the degree of closing of the throttle butterfly responsive to the relative motion of the throttle lever, the presence of ice at the throttle butterfly, and also may indicate the amount of such ice. This mechanism may automatically control the input of either the de-icing fluid or of the air preheat, or both, to cause the removal of ice and to interrupt the treatment when the ice has been removed.

These and various other objects, will be better understood by reference to the drawings, in

which:

Fig. l is a somewhat schematic arrangement of the carburetor showing the photoelectric ice warning system, and both the air preheating system and the de-icing fluid injection.

Fig. 2 shows the throttle valve ice warning system, showing open throttle free of ice.

Fig. 3 shows the same system and the throttle in partly closed condition and ice accumulation in the valve passage.

Fig. 1 shows the photoelectric element positioned in the passage between the throttle butterfly valve and the engine manifold which is not shown. This element may be placed on the other side of the'throttle. The particular photoelectric device illustrated in the drawing is a selenium cell, although other photoelectric tubes may be employed in its place. The photoelectric device as shown in Fig. 1 may be positioned at any convenient place where ice may form. In Fig. 1, l is the carburetor bowl, 2 is the air passage within which is positioned the main jet 3. The venturi of the carburetor is shown at l, positioned within the air passage 5 in which is also mounted the throttle valve or disc 5. Immediately beyond the throttle valve ,6 is a flange 1 upon which is mounted a photoelectric device by-means of the flange 8, suitably bolted together. The photoelectric element is composed of the air and fuel passage 9 in which are positioned diametrically opposed windows l2 and I3. These windows may be made of quartz, optical glass or plate glass, or clear plastics. Chamber It is mounted on the tubular passage 9 and in this chamber is mounted an electric bulb [5, so that the lightmay be transmitted through the window l2. Chamber I6 is mounted in juxtaposition with .the window l3. In this chamber is mounted a photoelectric device such as a selenium cell IT. The light passes through the window 13 and illuminates the photoelectric device H. The lamp I5 is connected by line l9 to the battery 20. .The other terminal of the battery is connected by lines 2!, switch 22, ballast tube 23a and line 24 to the other lamp lead I8. The selenium cell is connected by lines 25 and 26 to the microammeter 29 suitably provided with an adjustable shuntreslstance 21.

The wall of the passage 9 at a position 90 from aaeascs windows l2 and I3 carries a hollow chamber separated by a thin wall 30 from the interior of the passage 9. In this chamber is mounted a resistance wire 32 suitably electrically insulated from the metal of the wall. The element is also heat insulated from all portions of the wall of the passage 9 except opposite the thin wall 30 so that element 32 is made responsive to the temperature of the fluid in 9 and is not materially afiected by heat flow through the wall of 9 from other parts of the unit. The heat leakage may, also be diminished by positioning the thermoelectric element 32 in the butterfly valve 6. The resistance 32 is connected by lines 33 and 34 to the Wheatstone bridge 35. Battery 20 is connected to the bridge via lines 21, 22 and 24, and ballast tube or other voltage regulating device 23-a, the other terminal being connected to the bridgethrough the ballast tube 23. bridge is placed a galvanometer 38 connected by line 36 and 31 to the bridge.

A de-icing fluid injection nozzle 40 may be provided in the carburetor at a place somewhat below the main fuel injection jet 3. The motor-driven pump fill-a is connected to a tank containing the de-icing fluid to be injected through 60. The air passage to the carburetor is composed of the main air scoop 43 in which is positioned a baille M. An auxiliary air inlet 42 which may be the hot air coming from a typical installation of an intensifier system used in aircraft or from any other source of hot air, is provided as shown. The valve 45 operated by the lever 46 is so con structed as to shut ofi the cold air passage 63 when it is moved to its extreme position to the right or to shut oil the hot air inlet when moved to its extreme position to the-left. By adjusting its position to any intermediate point a proportioning of the hot and cold air may be obtained for the desired preheating of the air through 43. The commingled air, is mixed and introduced through the opening 61 into the main carburetor system.

The operation of the valve 45 and the pump 40--a may be made automatic by provision of an amplifying device 8| which amplifies the photoelectric current. The solenoid coil 82 which operates against the tension spring 93 holds the circuit open until the photoelectric current drops to a low level, when the circuit is closed by the spring 83a through the battery 20, and the solenoid 93. The solenoid armature 84 is connected to lever $6. The tension spring 86 connected to 85 is placed in desired tension by the tension screw 81 passing through the bracket 88;

' resistance wire 32, for instance copper wire, is

responsive to temperature changes,so that its resistance varies with temperature. As the temperature changes the resistance of this wire, the galvanometer needle is actuated, as is a' well known phenomenon in Wheatstone bridge arrangements. The ballast tube 23 functions to maintain a constant potential across the bridge. The other arms of the Wheatstone bridge may be made of wire with a low temperature resistance coeflicient, as for instance, manganin wire. By the proper design of the ballast tube and the arms of the Wheatstone bridge and the galvanometer, thegalvanometer may be set to record zero or balanced position (as illustrated in the drawings) Across the to the region marked below.

' ammeter 28.

out of the icing region either to its balanced poassasos ture rises above 32 F. the galvanometer will move into the region indicated as above, indicating that the temperature is above icing conditions. When the temperature drops below 32 F. the galvanometer will indicate "below, thus showing that the temperature is in a region where ice formation may be expected.

The shunt resistance 21 is adjusted so that the galvanometer indicates zero or balanced position (as illustrated on the drawings) with the light passing from the bulb l8 through the windows I: and I8 and illuminating the photoelectric device ll, This zero adjustment compensates for any diminution in light intensity arising from accidental dirtying of the windows I! and I3.

When the temperature drops to icing condi-, tions, the pilot is warned by the fact that he is' in a region where ice may be expected by reason of the movement of the, galvanometer needle 88 When ice is formed in the passage 8 it will cover windows l2 or l8, thus cutting down the intensity of the illumination of the photoelectric device H. The

diminution in photoelectric current passing through the microammeter 28 will move the microammeter into the region marked ice.

' When this occurs the microammeter needle or the decreased flow of current in the circuit 2828 may actuate a relay to start the pump indicated in the drawing to pump a mixture of alcohol and glycerine through the nozzle 88 into the air passage and through the venturi 8. This fluid depositing on the ice tends to make the ice mushy and the air stream will remove the ice from the passages. The removal of the-iice'causes a beam of greater intensity to reach photoelectric device i1, causing an increased current in the micro- The microammeter needle moves sition or perhaps into the "no ice" region, if the removal of ice has also for some reason removed any accidental dirt which has deposited on the windows. The increased current would then permit the relay to operate to stop the pump and therefore stop the injection of the de-icing fluid.

also be stopped by the opening of themotor-battery circuit at 88'. In this way the device can act automatically to inject the de-icing fluid or to cause a preheating of the air. Instead of an automatic operation, themovement of the lever arm 48 or the starting of the pump, the de-icing fluid through jet 48 may be manually controlled when the needle 28 indicates that ice is formed. The aocumulationof ice at the butterfly 8 may also beindicated by means or the devices illustrated in Figs. 2 and 3. In Fig. 2, the butterfly valve 8 is'actuated by the slotted arm 48, which in turn is actuated by means of the throttle arm 88. The lever 48 is slidably connected via pin" to the arm 88. Arm carries a cylinder 81 into which the arm 80 is screwed. In cylinder 8| is positioneda piston 82 mounted upon a piston rod 88 which passes through a hole in the cylinder head 84. Mounted underneath the piston 82 and within the cylinder 8| is a compression spring 88. The cylinder is provided with a slot 81 through which passe a contact arm 88 connected to the piston rod 88. Upon the bracket 80 connected to the cylinder'8l is mounted a resistance coil 88 wound upon an insulation rod 88'. The upper bracket 80 carries an insulation pin 88'. With the arm 88 at the top position, the

insulation pin holds the contact spring IO-Lb away from the bolt ,80a which is thus electri- The same relay may, it it is desired,- also actuate the lever arm 48 to move the lever arm to a midway position between the air passages 48 'and 48' to cause the injection of hot air. The actuation of the arm 48 is, as will be understood from the above description, caused by the energizing of the solenoid 88. When-the photoelectric current drops to a predetermined low flgwe the amplifled current issuing from 8| is insuflicient to energize the solenoid 82 to a degree suilicientto overcome the tension of the spring 88-a. Contact 88' is pulled downward. This may also be accomplished by manually closing 88'. The circuit is thus closed through the battery 20 and solenoid 88 moves the armature to the left against the tension of the spring 88 and lights the warning light-18.

If it is also'desired to cause the injection of the deicing fluid, switch Ill-b is-olosed and the Fig. 2 shows the throttle in open cally connected to ground. Theother end of the spring lib-b is fixed to bolt IO-c by means of the insulating washer 'I8a. The lower end of the piston 83 is connected through coupling 8! to the arm 83. Coupling 8| carries a set screw 82 and the rod 83 passes through a bracket 84 which may be any portion of the vehicle through which the throttle arm passes. The cylinder is grounded and is further connected through the bracket 88 line 10, relay coil H, to the battery 88. The other side of the battery is grounded at 88. The meter 88 is connected through line 8'! to the live side of the battery 88, and by line 88 V to resistance coil 88.

The pivoted contact 13 coacting with the flxed contact point I2, is connected to the live side of the battery 88 and through line 18 to the motor 88,

' the other side of which is grounded at 88. The

contact 18 isalso connected through the line 11 to the light 18. The other side of the light is grounded at 88.

position.

. When there is no ice present the compression rent flow through 82. The solenoid 88 will be de-energlzed and the spring 88 will close the hot air inlet 42. The motor "-a. of the pump will spring is of such strength that the pulling of the throttle arm 83 is insuflicient to compress the spring 88 and the arm and arm 83 and the cylinder 8| moves as a unit to actuate the throttle butterfly. I

As the contact 88 moves downwardly, the spring ill-b presses against the bolt 80-0, closing the circuit to ground. The contact 88 being in contact with the insulation 88', keeps an open circult in 88 and 18 and therefore the contact 18 -is not actuated and remains open and no current flows through the meter 88. With the contact open, the light 18 is dark and the motor" is not actuated. Assume, however, ice has collected onthe interior of the wall 8 (see Fig. 3). The closing of the throttle moves the butterfly 8 until it contacts the ice, which would be at a position short of closed position of the butterfly; The continued movement of the throttle arm will not further close the butterfly, but will compress the spring 58. The piston is moved downward in the cylinder 8| and the contact 88 moves off from the insulated portion onto the resistance 88.- This closes the circuit; through the battery and through the meter 86. The meter 66 will indicate the position of the arm 56 upon resistance 58, since the flow of current through the meter 66 will be proportional to the resistance in the circuit. This will indicate the amount of ice which has accumulated inside the wall 5. The

rod 63 is always moved to th full extent of its motion, that is, until the set screw 62 contacts with the bracket 65. The closing of the circuit thus produced energizes the coil II and pulls the contact 15 down against the contact 12,

against the resistance of tension spring It, and

motor 80. This motor 80 may be connected to the pump for pumping of the fluid through jet 5B, and may also actuate the arm 46 to admit hot air, by energizing the solenoid 83, which may be constructed and operated as illustrated in connection with Fig. 1. When the ice has been removed from the walls 5, the compression spring will automatically move the cylinder downwardly, thus resulting in a relative upward movement of the contact on the resistance to diminish the resistance in the ammeter circuit and to indicate an increased fiow of current. The removal of the ice may be followed on the meter 66, since as the ice is being removed and the resistance is decreasing, an increased flow of current will be shown on 66, When this flow of current is of such magnitude as to indicate that all the ice has been removed, as will occur when the contact moves onto the insulation and the circuit through the meter is broken and the meter drops to zero, the pilot may manually pullthe rod ?5, thus breaking the toggle. Since the circuit through the coil Ii is broken becaus of the positioning of the contact 56 upon the insulation 5%, the coil II is deenergized, the spring 74 opens the contact at 52, and the light 1% will go out and the motor at will stop.

Upon return of the contact 5G to the upward position, the insulatin pin 66' is pushed upward, thus lifting the spring id-b to open the circuit from ill to ground.

In order to permit of a greater surface of contact between the throttle and the ice formed as shown in Fig. 3, semi-circular wedge-shaped flanges 89 as shown in Fig. 3 are provided.

It is to be understood that the foregoing embodiments of my invention are illustrative only e therein within the scope of the appended I claim: V

1. Means responsive to the accumulation of ice in a carburetor system comprising a means for mixing air and fuel, a fuel passage through which said commingled fuel and air passes, a photoelectric element, a source of light, means for passing said light through said fuel passage to energize said photoelectric element, an electric circuit including said photoelectric element, and means in said circuit responsive to the variation in intensity of the beam of light.

-2. Means responsive to the accumulation of ice in a. carburetor system comprising a means for mixing air and fuel, a fuel passage through which said commingled fuel and air passes, a mixing venturi, a throttle, a passageway beyond said venturi, a plurality of opposed windows in the walls of said passage, a light source at one of said variations of intensity of illumination upon said photoelectric element resulting from accumulation of ice on said windows, and, means respons ve to said last named means for controlling the temperature of the air entering said carburetor.

a. A carburetor system comprising a means for mixing air and fuel, a. fuel passage through which said commingled fuel and air passes, a mixing venturi, a throttle, a passageway beyond said venturi, a, plurality of opposed windows in the walls of said passageway, a light source at one of said windows, a photoelectric element at another of said opposed windows, an electrical circuit including said photoelectric element,

means in said electrical cincuit responsive to the variations of intensity of illumination upon said photoelectric element resulting from accumulation of ice on said windows, means responsive to said last named means, and means for modifying the temperature of said air entering the can buretor system, including a cold air inlet, a hot air inlet, and means for proportioning the mixture of hot air and cold air, said last named means being controlled by said means responsive to the variations of intensity of illumination upon said photoelectric element.

JOHNF. CARSSOW. 

